Highest I've EVER been by far was the first time I bought a bag, second time I ever smoked. It was some mids and me and a friend of mine smoked through maybe 1-1.5 Gs. I was told later it was laced with hydrocodone, which probably had something to do with it, and I had taken 50 mg of Adderall earlier in the night, AND I had no tolerance to any drugs whatsoever at the time, but the point is...I was SOOOOOOO high. Still been chasing that dragon and it's been a few years now. Most I've ever smoked at once...smoked through a whole 8th of good dank in a few hours on DOC...my god was I high. And between 4-5 friends, I'd say we've gone through 8ths of dank quite a few times, and definitely more mids. There is a ceiling effect at some point, but that can usually even be overcome; it depends more on strain than anything IMO.